1. Field of the Invention
The present invention relates to an electrocardiograph and a display method for the electrocardiograph, and in particular to a portable electrocardiograph having a display function and a display method for the portable electrocardiograph in which the image on display can be easily viewed.
2. Description of the Related Art
An electrocardiogram is used as an effective method of diagnosing heart diseases such as myocardial infarct, angina cordis and ischemic heart disease. In order to diagnose these heart diseases more effectively, the use of the electrocardiogram at the time of occurrence of an abnormality such as a chest pain or palpitation in daily life is desirable for early identification and proper treatment of such diseases. For this reason, there is presently a technique called a 24-hour electrocardiograph, in which the electrocardiographic waveform measured and obtained from the induction electrodes worn for 24 hours by the subject is recorded in a recording device.
The measurement of the electrocardiographic waveform using the 24-hour electrocardiograph, however, imposes a considerable burden on the subject, and it may happen that no abnormality occurs during the measured 24-hour period. In recent years, therefore, a portable electrocardiograph has been proposed to measure the electrocardiographic waveform positively at the time of an abnormality with little burden on the subject, thereby making it possible to measure the electrocardiographic waveform when an abnormality occurs.
This electrocardiograph recently used, as described in Japanese Unexamined Patent Publication No. 1-502087 (hereinafter referred to as Reference 1), has a display on the body of the electrocardiograph to check the measurement in situ.
In measuring the electrocardiographic waveform by holding a grip of the electrocardiograph body including one of the induction electrodes by hand while bringing the other induction electrode into contact with the breast or abdomen constituting an electrode contact portion, however, the direction of the measurement result (graph) displayed on the display may fail to coincide with the direction in which the subject in measurement position can visually check the display, thereby sometimes posing the problem that the image on display is hard to observe. Changing the position to facilitate observation, however, may disrupt the measurement position and make correct measurement impossible.